Apparatus fob the ignition of



May 9, 1950 w. B. SMITS APPARATUS FOR THE IGNITION 0F EXPLOSIVE MATERIAL IN A LIQUID Filed Oct. 18, 1946 Patented May 9, i950 APPARATUS FOR THE IGNITIVON F EXPLOSIVE MATERIAL m A LIQUID Wm. Beye Smits, Wassenaar, Netherlands Application October 18, 1946, Serial No. 704,023 In the Netherlands November 1, 1945 1 Claim. 1

The invention relates to an apparatus for the ignition of explosive material in a liquid, particularly for the ignition under water of a welding or cutting torch.

For purposes such as bridge building and ship salvage oxy-acetylene torches are often used for cutting and weldin metal parts under water. While at such work many difficulties are encountered. For instance, the torch is easily extinguished under water when the nozzle of the torch touches the metal to be cut or by strong currents in the water. For its re-ignition the torch must be pulled up to the surface of the water and, after its ignition, lowered'again very carefully to the diver. It will be evident that by this operation much time is wasted. Moreover, accidents are liable to occur.

The present invention solves the problem and provides an apparatus for the ignition of explosive material, for instance a mixture of oxygen and acetylene, in a liquid, e. g. water. With the aid of this apparatus a diver is able to ignite his welding torch under water as easily as above the surface of the water. The apparatus according to the invention substantially comprises a spark gap for the igniting spark, e. g. a normal sparking plug, a condenser, a device for charging said condenser up to voltages higher than 100 volts and means by the aid of which said condenser can be discharged through said spark gap. The device for charging the condenser may be provided with a first circuit comprising a source of direct current, the low tension winding of a transformer and an oscillatin interrupter for the periodical interruption of said circuit, and with a second circuit, in which the high tension winding of said transformer, a second spark gap and the condenser are inserted. The parts for discharging the condenser may constitute a third circuit comprising said condenser, a third spark gap and the above-mentioned first spark gap for the igniting spark, e. g. the sparking plug.

These and other features of the invention will be elucidated hereinafter with the aid of the drawing, illustrating by way of example a sectional and diagrammatical view of an apparatus according to the invention.

The apparatus shown consists of two parts, an igniting torch I and a device I!) for the generation and the conversion of the energy required for the sparks. The torch I is constituted by a tube I on one end of which a sparking plug 2 constituting the first spark gap I B is mounted. Said sparking plug is held in position by a cap screwed on said tube and it closes the latter in 2 a watertight manner by means of a rubber washer 4. Mounted within space 5 of tube I is a mercury switch 8 for purposes which will be explained hereinafter. The torch is connected to device III by a cable 1 penetratin both the other end of torch I and the upper wall of casing In by means of a watertight packing gland 8, 9 and 29 respectively.

In casing In a so-called induction coil II provided with a built-in interrupter I2, a second spark gap I3, a condenser II, a third, spark gap I5, a battery I1 and a switch [8 operable from the outside are accommodated. One pole 0! battery I1 is connected by a conductor-A of cable I to mercury switch 6 and hence by a conductor B of said cable to one end of the low tension winding 22 of the induction coil and one end of the coil of an electro-magnet for the operation of interrupter I2. The other ends of winding 22 and magnet coil 36 are connected through the contacts 20 of interrupter I2 and switch I8 to the other pole of battery I'I. As a rule contacts 20 are closed. When switch I8 is closed and the torch I is held in a position in which the mercury 23 connects the contact =25 to the metal tube 24, that means connects the conductors A and B to one another, current flows through primary 22 and coil 36 is energised. Then, the electro-magnet attracts interrupter I2 and opens contacts 20. By the sudden interruption of the circuit of primary 22 the magnetic ilux of the induction coil breaks down and in the high tension or secondary winding 22a thereof a current impulse of high voltage is generated. When the contacts 20 open the primary circuit, electromagnet 36 is de-energized at the same time, loses its grip on interrupter I2 and permits the latter to close its contacts 20 again. Consequently coil 36 is energised again and contacts 20 are opened for the second time. Obviousb', the interrupter I2 will oscillate and cause frequent break downs of the magnetic flux in the induction coil and so generate current impulses of high tension in secondary 22a. These impulses are conducted into a second circuit comprising spark gap l3 and condenser I4. When the voltages of the impulses are high enough the gap I3 is ruptured and condenser l4 will be charged.

Condenser I4 is inserted into a third circuit comprising spark gap I 5, conductor C of cable I, spark gap I6 of the sparking plu 2, the body of torch 3, I and conductor B of cable I. As soon as condenser I4 is charged to a certain voltage gap I5 is ruptured and a sparkof great intensity is produced between the electrodes 0! assays-r7 sparking plug 2. Preferably, spark gaps I3 and It are adjustably mounted for the regulation 01 the frequency of the igniting sparks. It appeared to be advantageous to adjust spark gaps l3 and It in such a manner, that every second one igniting spark is produced.

Torch l is provided with a hook-shaped member 35 by means of which the torch can be hung on a part of the body to be welded or cut or on the diving-dress. When torch l is hanging by means of its hook 35 the mercury 23 is situated at the opposite end within tube 24 and the con tact between conductors A and B is broken. In that position the ignition system does not work. If the diver has to ignite his welding or cutting torch he simply has to turn the igniting torch I into the position in which the sparking plug is on top. In that position mercury switch 6 closes the primary circuit of the ignition coil H, which immediately starts to charge condenser I 4.

Casing l and the parts accommodated therewithin may remain out of the water. However, since it has a waterproof construction the diver may take it with him into the water. Advantageously it is so constructed that it is slightly heavier than the amount of water it displaces, so that it can be easily displaced by the diver when he is in the water.

Casing I0 is divided into two separated spaces 26 and 21. Space 26 contains the complete induction coil l'l, condenser I4 and spark gaps l3 and i5. Space 21 houses the battery and is provided in one of its walls with a check valve 2| permitting the gases, developed by the battery, to

escape. Casing III has legs 34 permitting it to stand upon the bottom of the sea, lake or river. By means of a pinching member 30, attached to casing III by a chain, said casing may be hung on parts of thebody to be welded or to be cut.

' For charging purposes battery I! may be connected to terminals on the outside of easing ID. V It may be noted, that sparks produced by the discharge of a condenser are very intense when the electrodes of the sparking plug are bridged 4 by semi-conductive material. In the present cases both fresh water and salt-water must be considered as semi-conductors improving the generation of very intense sparks.

In the embodiment shown in the drawing the electrodes of sparking plug 2 are protected by screw-cap 3 which is perforated for the admission of the gas to be ignited.

What I claim is:

Apparatus for the ignition of a welding torch or the like under water, comprising a spark plug adapted for immersion in water, a storage capacitor, electrodes defining therebetween an auxiliary spark gap, conductors connecting said spark plug and said electrodes in a series circuit including said capacitor, a source of direct current, an electromagnetic interrupter provided with contacts, a circuit including said source and said interrupter, a manually operable switch in said circuit, a transformer having a primary winding connected inseries with said current source and said contacts and having a secondary winding one end of which is connected to one side of said capacitor, and electrodes forming an additional spark gap connected between the other end of said secondary winding and the other side of said capacitor.

WYTZE BEYE SMITS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 774,624 Waters et al Nov. 8,1904 1,324,337 Chapman Dec. 9, 1919 1,326,215 Sencenbaugh Dec. 30, 1919 1,476,725 Pope Dec. 11, 1923 1,482,098 Stocking Jan. 29, 1924 1,537,903 Von Lepel May 12, 1925 1,865,583 Onken July 5, 1932 2,326,696 Stoddard Aug. 10, 1943 

